Re: Linux 2.6.20-rc7



On Wed, 31 Jan 2007, PaweÅ Sikora wrote:

The 2.6.20-rcX have the same nasty bug as 2.6.19.x.

[ an oops inside kmem_get_pages ]
http://bugzilla.kernel.org/show_bug.cgi?id=7889

Pabel, can you detail more exactly which kernels don't work, and which do?

From bugzilla:

- 2.6.18.x does work
- 2.6.19.2 doesn't work.
- what about plain 2.6.19?
- can you please test some of the 2.6.19-rcX kernels? Especially
2.6.19-rc1 would be good to test.

Since it apparently already happens in 2.6.19 (but it would be really good
to know exactly when it starts), and considering _where_ it happens, I'd
be inclined to blame commit d2e7b7d0: "fix potential stack overflow in
mm/slab.c" by Suresh.

When do_tune_cpucache() is called at bootup, I'm not sure how safe it is
to do the kzalloc() thing.

I've added a number of hopefully appropriate people to the Cc. Guys?
Apparently it only happens with MEMORY_HOTPLUG (and possibly with just an
SMP kernel on UP), which probably explains why it's been around without
people really complaining very loudly.

Linus